Drive mechanism for an indicator of the date or the days of the week

ABSTRACT

A driving mechanism for a date-or-day indicator comprises a gear driven at the rate of n revolutions daily and carrying a pivotal lever adapted for meshing with a drive gear secured to the indicator. The lever is moved by a cam coaxial with the drive gear and located in the same plane of the lever and revolving at the rate of (n + 1) revolutions daily in the same direction as the driven gear so that a nose of the cam causes the lever to enter once every 24 hours into the path of the drive gear to advance the indicator.

United States Patent Golay et al.

[451 May 23, 1972 [72] Inventors: Jean-Pierre Golay; Bernard Gerber,both of Tramelan, Switzerland Record Watch Co., S.A., Tramelan,Switzerland 22 Filed: Sept. 21, 1970 211 App]. No.: 74,071

[73] Assignee:

2,948,107 8/1960 Marmier ..58/58 3,436,905 4/1969 Giger ..58/583,439,493 4/1969 Mutter et al. ..58/58 FOREIGN PATENTS OR APPLICATIONS1,563,142 4/1969 France ..58/58 Primary Examiner-Richard B. WilkinsonAssistant Examiner-George H. Miller, Jr. Att0meyWaters, Roditi, Schwartz& Nissen [57] ABSTRACT A driving mechanism for a date-or-day indicatorcomprises a gear driven at the rate of n revolutions daily and carryinga pivotal lever adapted for meshing with a drive gear secured to theindicator, The lever is moved by a cam coaxial with the drive gear andlocated in the same plane of the lever and revolving at the rate of (nl) revolutions daily in the same direction as the driven gear so that anose of the cam causes the lever to enter once every 24 hours into thepath of the drive gear to advance the indicator.

1 1 Claims, 3 Drawing Figures BRIEF SUMMARY OF THE INVENTION Theinvention relates to a driving mechanism for a day or date indicator ofa timepiece.

A problem in driving date-or-day indicators is the need for thechangeover to take place once each day in the shortest possible time.

To effect such quick changeover, the present invention contemplates adriving mechanism of a timepiece for an indicator indicating the day ofthe month or the days of the week.

According to the invention, the driving mechanism comprises a gearsecured to the indicator to drive the same, a rotary member driven atthe rate of n revolutions daily, an actuating lever pivotably connectedto said rotary member and rotatable therewith, and cam means rotating atthe rate of n l revolutions daily and engageable with said actuatinglever to pivot the same once every 24 hours into a position in drivingrelation with said gear to cause the lever to advance the gear and theindicator therewith at the rate of speed of the rotary member.

Two such driving mechanisms can be paired so as to drive a day and adate indicator simultaneously.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view partly brokenaway showing one embodiment according to the invention;

FIG. 2 is a perspective view of a portion thereof; and

FIG. 3 is a section taken along line IIIIII of FIG. 2.

DETAILED DESCRIPTION The drawing shows an embodiment of a date and a dayindicator movement and first the day indicator movement will bedescribed in detail.

The day indicator movement comprises a rotatable plate at the peripheryof which are inscribed the days of the week. A gear 4 is secured to theplate 1 for common rotation therewith. The gear 4 is advanced once every24 hours by an arm 3 of a lever 5 as will be explained later. The lever5 is pivotably connected by a pin 6 to a gear 7 which is driven inrotation so as to make n revolutions daily.

Lever 5 is in abutment with a cam 8 coaxial with gear 7 and rigidlyconnected with a gear 10 driven in rotation at the rate of n 1revolutions daily. The cam 8 and lever 5 lie in a common plane abovegear 7. The passage of a nose 9 on cam 8 pposite lever causes the arm 3on lever 5 to engage the teeth of gear 4 as shown in FIG. 1 and torotate the gear 4 in concert with the gear 7.

A resilient detent 11 holds the indicator plate 1 in position until theplate is driven by arm 3.

The gear 4 is driven by arm 3 to advance the plate and position the nextday in the window shown in chain dotted outline in FIG. 1.

The drive of the gears 7 and in the ratio of n/( n+1) revolutions eachday is obtained by a pair of gears 12 which are driven by the watchmovement.

Because, the arm 3 drives the gear 4 at the rate of rotation of the gear7, the gear 4 will be driven n times as fast as compared to aconventional arrangement in which the arm is driven at the rate of lrevolution per day. Thus the day change will take place n times morequickly. In practice, it has been found preferable to select the orderof magnitude of n as 8.

Reference will next be made to FIG. 3 which shows in greater detail thecomponents of the drive for a toothed date indicator rim 2. This driveis mounted beneath gear 7, symmetrical to the drive described forplate 1. The advance of rim 2 is effected by arm 3 shown in FIGS. 1 and2. The arm 3' is on a lever 5 (FIG. 3) identical to lever 5, but mountedon the lower face of gear 7, symmetrical to lever 5. The lever 5 ispivotably mounted on gear 7 on pin 6' symmetrical with pin 6.

The lever 5' is actuated by a cam 8 identical to cam 8, the cam 8 beingmounted in the same plane as the lever 5 and symmetrically with cam 8.Cam 8' is also rigidly connected to gear 10 and is driven at a rate of n1 revolutions daily, so

that the drive of the date indicator rim 2 takes place under the sameconditions as that of the day indicator plate I and, in particular, atthe same speed.

Cams 8 and 8' are each in the shape of a curvilinear triangle whosethree sides are formed by three identical arcs. The cams are drivenabout respective axes which are offset from their centers of symmetry.

Levers 5 and 5 have a profile such that they are positively driven bythe respective cams and therefore require no return spring.

Obviously a different profile requiring springs could also be employed.

It should be noted that rim 2 makes one revolution a month and thatplate 1 carries two series of the seven days of the week and makes onehalf-revolution each week. Without such arrangement, the pitch of theteeth of gear 4 would become too large unless such wheel were of verysmall diameter.

From the above it is seen that the day and date indicators are advancedat a speed of n revolutions daily by carrying the actuator levers 3 and3 on rotary gear 7 rotating at n revolutions daily and moving the leversinto operative driving positions with respect to their indicators onceevery 24 hours by means of the cams 8 and 8' which rotate about an axiscommon with the gear 7 at a speed of n l revolutions daily. By the abovearrangement, the cams each make one revolution daily relative to thegear 7 thereby effecting movement of the levers to operative positiononce every 24 hours.

What is claimed is:

1. A driving mechanism for a day or date indicator, said mechanismcomprising a gear secured to the indicator to drive the same, a rotarymember driven at the rate of n revolutions daily, an actuating leverpivotably connected to said rotary member and rotatable therewith, andcam means rotating at the rate of n 1 revolutions daily and engageablewith said actuating lever to pivot the same once every 24 hours into aposition in driving relation with said gear to cause the lever toadvance the gear and the indicator therewith at the rate of speed of therotary member.

2. A driving mechanism as claimed in claim 1 wherein said cam means andsaid rotary member rotate around a common axis.

3. A driving mechanism as claimed in claim 2 wherein said cam means islocated in the same plane as the actuating lever.

4. A driving mechanism as claimed in claim 3 wherein said actuatinglever includes an arm which engages said gear, and said cam meanscomprises a cam having a nose which engages the lever to introduce theam into engagement with said gear.

5. A driving mechanism as claimed in claim 4 wherein the cam and leverare shaped so that the lever is positively driven by the cam throughout360 rotation of the cam.

6. A driving mechanism as claimed in claim 4 wherein n is 8.

7. A driving mechanism as claimed in claim 4 comprising a first geardriving said rotary member and a second gear coaxial with said firstgear and of different diameter driving said cam.

8. A driving mechanism as claimed in claim 4 comprising a secondindicator, one indicator for the day, the other for the date, and asecond driving mechanism including an actuating lever and a camsymmetrically disposed with respect to said rotary member. 1

9. A driving mechanism as claimed in claim 8 comprising a common shaftfor said rotary member and said cams, said shaft passing through saidlevers, the cam and actuating lever of one drive mechanism beingdisposed at one face of said rotary member, while the came and actuatinglever of the other driving mechanism are disposed at the opposite faceof the rotary member.

10. A driving mechanism as claimed in claim 9 wherein said arms of thetwo actuating levers are diametrically opposite one another, the gearsecured to one indicator being an external gear and the gear secured tothe other indicator being an internal gear, one am being engaged withthe external gear while the other is engaged with the internal gear sothat the arms drive said indicators simultaneously.

1 l. A driving mechanism as claimed in claim wherein the indicator forthe days of the week includes the seven days of 5 the week repeated atleast once at the periphery of the corresponding indicator.

1. A driving mechanism for a day or date indicator, said mechanismcomprising a gear secured to the indicator to drive the same, a rotarymember driven at the rate of n revolutions daily, an actuating leverpivotably connected to said rotary member and rotatable therewith, andcam means rotating at the rate of n + 1 revolutions daily and engageablewith said actuating lever to pivot the same once every 24 hours into aposition in driving relation with said gear to cause the lever toadvance the gear and the indicator therewith at the rate of speed of therotary member.
 2. A driving mechanism as claimed in claim 1 wherein saidcam means and said rotary member rotate around a common axis.
 3. Adriving mechanism as claimed in claim 2 wherein said cam means islocated in the same plane as the actuating lever.
 4. A driving mechanismas claimed in claim 3 wherein said actuating lever includes an arm whichengages said gear, and said cam means comprises a cam having a nosewhich engages the lever to introduce the arm into engagement with saidgear.
 5. A driving mechanism as claimed in claim 4 wherein the cam andlever are shaped so that the lever is positively driven by the camthroughout 360* rotation of the cam.
 6. A drivIng mechanism as claimedin claim 4 wherein n is
 8. 7. A driving mechanism as claimed in claim 4comprising a first gear driving said rotary member and a second gearcoaxial with said first gear and of different diameter driving said cam.8. A driving mechanism as claimed in claim 4 comprising a secondindicator, one indicator for the day, the other for the date, and asecond driving mechanism including an actuating lever and a camsymmetrically disposed with respect to said rotary member.
 9. A drivingmechanism as claimed in claim 8 comprising a common shaft for saidrotary member and said cams, said shaft passing through said levers, thecam and actuating lever of one drive mechanism being disposed at oneface of said rotary member, while the came and actuating lever of theother driving mechanism are disposed at the opposite face of the rotarymember.
 10. A driving mechanism as claimed in claim 9 wherein said armsof the two actuating levers are diametrically opposite one another, thegear secured to one indicator being an external gear and the gearsecured to the other indicator being an internal gear, one arm beingengaged with the external gear while the other is engaged with theinternal gear so that the arms drive said indicators simultaneously. 11.A driving mechanism as claimed in claim 10 wherein the indicator for thedays of the week includes the seven days of the week repeated at leastonce at the periphery of the corresponding indicator.